CURLOPT_HTTPHEADER(3)      curl_easy_setopt options      CURLOPT_HTTPHEADER(3)

NAME
       CURLOPT_HTTPHEADER - set custom HTTP headers

SYNOPSIS
       #include <curl/curl.h>

       CURLcode   curl_easy_setopt(CURL  *handle,  CURLOPT_HTTPHEADER,  struct
       curl_slist *headers);

DESCRIPTION
       Pass a pointer to a linked list of HTTP headers to pass to  the  server
       and/or  proxy  in your HTTP request. The same list can be used for both
       host and proxy requests!

       The linked list should be a  fully  valid  list  of  struct curl_slist
       structs properly filled in. Use curl_slist_append(3) to create the list
       and curl_slist_free_all(3) to clean up an entire list.  If  you  add  a
       header that is otherwise generated and used by libcurl internally, your
       added one will be used instead. If you add a header with no content  as
       in  'Accept:'  (no data on the right side of the colon), the internally
       used header will get disabled. With this option you can add  new  head-
       ers,  replace  internal  headers  and remove internal headers. To add a
       header with no content (nothing to the right side of  the  colon),  use
       the form 'MyHeader;' (note the ending semicolon).

       The  headers  included  in the linked list must not be CRLF-terminated,
       because libcurl adds CRLF after each header  item.  Failure  to  comply
       with  this  will  result  in  strange bugs because the server will most
       likely ignore part of the headers you specified.

       The first line in a request (containing the method, usually  a  GET  or
       POST)  is  not  a header and cannot be replaced using this option. Only
       the lines following the request-line are headers.  Adding  this  method
       line  in  this  list of headers will only cause your request to send an
       invalid header. Use CURLOPT_CUSTOMREQUEST(3) to change the method.

       When this option is passed to  curl_easy_setopt(3),  libcurl  will  not
       copy the entire list so you must keep it around until you no longer use
       this handle for a transfer before you  call  curl_slist_free_all(3)  on
       the list.

       Pass a NULL to this option to reset back to no custom headers.

       The most commonly replaced headers have "shortcuts" in the options CUR-
       LOPT_COOKIE(3), CURLOPT_USERAGENT(3) and CURLOPT_REFERER(3). We  recom-
       mend using those.

       There's  an  alternative  option that sets or replaces headers only for
       requests that are sent with CONNECT to a proxy: CURLOPT_PROXYHEADER(3).
       Use CURLOPT_HEADEROPT(3) to control the behavior.

SECURITY CONCERNS
       By  default,  this  option  makes libcurl send the given headers in all
       HTTP requests done by this handle. You should therefore use this option
       with  caution  if  you  for  example connect to the remote site using a
       proxy and a CONNECT request, you should to consider if  that  proxy  is
       supposed to also get the headers. They may be private or otherwise sen-
       sitive to leak.

       Use CURLOPT_HEADEROPT(3) to make the headers only get sent to where you
       intend them to get sent.

DEFAULT
       NULL

PROTOCOLS
       HTTP

EXAMPLE
       CURL *curl = curl_easy_init();

       struct curl_slist *list = NULL;

       if(curl) {
         curl_easy_setopt(curl, CURLOPT_URL, "http://example.com");

         list = curl_slist_append(list, "Shoesize: 10");
         list = curl_slist_append(list, "Accept:");

         curl_easy_setopt(curl, CURLOPT_HTTPHEADER, list);

         curl_easy_perform(curl);

         curl_slist_free_all(list); /* free the list again */
       }

AVAILABILITY
       As long as HTTP is enabled

RETURN VALUE
       Returns CURLE_OK if HTTP is supported, and CURLE_UNKNOWN_OPTION if not.

SEE ALSO
       CURLOPT_CUSTOMREQUEST(3), CURLOPT_HEADEROPT(3), CURLOPT_PROXYHEADER(3),
       CURLOPT_HEADER(3)

libcurl 7.54.0                 February 03, 2016         CURLOPT_HTTPHEADER(3)